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Cocoons of Parasitic Wasps (08/05/21)


These cocoons are ‘good’ beneficial insects or parasitic wasps in the insect family Braconidae. These tiny parasitic wasps (or parasitoids) lay multiple eggs within foliage-feeding caterpillars, such as armyworms or loopers. Eggs hatch into larvae, and they eat the insides of the caterpillar, thus killing it. Parasitism by the braconid wasps often causes the caterpillar to crawl to the tip of the plant, and it turns it into a zombie. Each mature larva of the wasp emerges and then spins a cocoon outside the caterpillar body. Extension Entomology has received many calls/emails/texts about these Braconid cocoons and whether it is a friend or foe on field crops. It is being observed on wheat/barley awns and on soybean leaves.

Cocoons of Braconid parasitic wasp found south of Dunn Center
Photo Credit:
M. Schollmeyer, grower


Janet J. Knodel

Extension Entomologist